Proposal of Helicobacter higonensis sp. nov. isolated from a human clinical specimen, and emended description of Helicobacter valdiviensis Collado, 2014.

We have previously isolated a gram-negative microaerophilic strain, PAGU2000T from a patient presenting with a fever in Kumamoto Prefecture, Japan. The present study aimed to comprehensively analyze the taxonomy of the isolated strain using a polyphasic approach. The 16S rRNA gene sequence analysis indicated that the strain was a member of enterohepatic Helicobacter. The strain PAGU2000T shared a 97.5% 16S rRNA gene nucleotide identity with Helicobacter valdiviensis, and this taxonomic position was confirmed by phylogenetic analysis of the GyrA amino acid sequences. The proposed strain PAGU2000T has a 1.482 Mbp chromosome with a DNA G + C content of 31.3 mol% and encodes 1520 predicted coding sequences. The average nucleotide identity between the strain PAGU2000T and type strain of H. valdiviensis was 70.3%, which was lower than the recommended threshold of 95% for species delineation. The strain PAGU2000T was a motile, non-spore-forming, and spiral-shaped bacterium, exhibiting catalase and oxidase activities but not urease and nitrate reduction. This study demonstrates that the isolate represents a novel species within enterohepatic Helicobacter, for which the name Helicobacter higonensis is proposed (type strain: PAGU2000T = GTC 16811T = LMG 33095T). In this study, we describe the phenotypic and morphological features of this strain and propose an emended description of some biochemical traits of H. valdiviensis.

Quantification of Oversupply of Chronic Disease Medications among Patients Aged ≥55 Years in Japan.

Medication waste may be caused by medication oversupply; however, the degree of medication oversupply in Japan is unclear. This study aimed to quantify the degree of oversupply of chronic disease medications per patient, the proportion of oversupplied patients, and the excess days and costs of the oversupplied medications in Japan. This retrospective nationwide cohort study using a large insurance claims database from Japan was conducted in patients aged ≥55 years who received one or a combination of the following five classes of medications dispensed in FY 2019: third-generation calcium antagonists, angiotensin 2 receptor blockers, statins, dipeptidyl peptidase-4 inhibitors, and biguanides. Medications with the same ingredient having the same specification were treated as the same medication. Medication oversupply was defined as a medication possession ratio (MPR) during persistence >1.0. The proportions of oversupplied patients and excessively oversupplied patients with ≥30 excess days/year were approximately 16 and 1-2% for all drug classes, respectively. Three-quarters of the oversupplied patients had fewer excess day (≤14/year), and the median oversupplied medication cost was less than 1000 yen/year for all classes. However, there was a patient with oversupplied medication estimated as 983 excess days per year and a patient with oversupplied medication costs of nearly 90000 yen per year. Using the MPR and excess days as indicators, it is necessary to accelerate estimation of the oversupply per patient, as well as the development of patient intervention strategies and a national system to reduce medication oversupply.

Helicobacter kumamotonensis sp. nov., isolated from human clinical specimens.

A Gram-stain-negative, spiral bacterium (PAGU 1991T) was isolated from the blood of a patient with diffuse large B-cell lymphoma. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was very closely related to Helicobacter equorum LMG 23362T (99.1 % similarity), originally isolated from a faecal sample from a healthy horse. PAGU 1991T was also very closely related to PAGU 1750 in our strain library (=CCUG 41437) with 99.7 % similarity. Additional phylogenetic analyses based on the 23S rRNA gene sequence and GyrA amino acid sequence further supported the close relationship between the two human isolates (PAGU 1991T and PAGU 1750) and the horse strain. However, a phylogenetic analysis based on 16S rRNA showed that the two human isolates formed a lineage that was distinct from the horse strain (less than 99.2 % similarity). In silico whole-genome comparisons based on digital DNA-DNA hybridization, average nucleotide identity based on blast and orthologous average nucleotide identity using usearch between the two human isolates and the type strain of H. equorum showed values of less than 52.40, 93.47, and 93.50 %, respectively, whereas those between the two human isolates were 75.8, 97.2, and 97.2 %, respectively. These data clearly demonstrated that the two human isolates formed a single species, distinct from H. equorum. Morphologically, the human isolates could be distinguished by the type of flagella; the human isolates showed a bipolar sheathed flagellum, whereas that of H. equorum was monopolar. Biochemically, the human isolate was characterized by growth at 42 °C under microaerobic conditions and nitrate reduction unability. We conclude that the two human isolates, obtained from geographically and temporally distinct sources, were a novel species, for which we propose the name Helicobacter kumamotonensis sp. nov., with the type strain PAGU 1991T (=GTC 16810T=CCUG 75774T).

Siderophore-producing Pantoea ferrattrahens sp. nov. isolated from a clinical specimen and Pantoea ferramans sp. nov. isolated from soil at the bottom of a pond.

Two Gram-negative facultative anaerobes were isolated from a sepsis patient with pancreatic cancer (strain PAGU 2156T ) and soil at the bottom of a pond (strain PAGU 2198T ), respectively. These two strains formed haloes around the colonies on chrome azurol S agar plates, indicating the production of siderophores. Two isolates assigned to the genus Pantoea based on the 16S rRNA gene were differentiated from established species by using polymorphic taxonomies. Phylogenetic analysis using four housekeeping genes (gyrB, rpoB, atpD, and infB) showed that strain PAGU 2156T is closely related to Pantoea cypripedii LMG 2657T (89.9%) or Pantoea septica LMG 5345T (95.7%). Meanwhile, strain PAGU 2198T formed a single clade with Pantoea rodasii DSM 26611T (93.6%) and Pantoea rwandensis DSM 105076T (93.3%). The average nucleotide identity values obtained from the draft genome assembly showed ≤90.2% between strain PAGU 2156T and closely related species and ≤81.5% between strain PAGU 2198T and closely related species. Based on various phenotypes, biochemical properties, and whole-cell fatty acid composition compared with related species, it was concluded that each strain should be classified as a new species of the genus Pantoea. In this manuscript, Pantoea ferrattrahens sp. nov. and Pantoea ferramans sp. nov. with strain PAGU 2156T (=NBRC 115930T = CCUG 76757T ) and strain PAGU 2198T (=NBRC 114265T = CCUG 75151T ) are proposed as each type strain.

Statin persistence and adherence among older initiators: A nationwide cohort study using the national health insurance claims database in Japan.

PURPOSE: This study clarifies the reality of persistence and adherence to statins in older Japanese people who initiated statin use and compares it between primary and secondary prevention cohorts. METHODS: The nationwide study using the national claims database targeted statin initiators aged ≥55 years from FY2014 to FY2017 in Japan. Persistence and adherence to statins were analyzed overall and according to subgroups based on sex, age stratum, and prevention cohorts. Permissible gap of median days that statins were supplied per prescription to an individual was employed. Persistence rates were estimated as Kaplan-Meier estimates. Poor adherence during persistence was evaluated and defined as <0.8 of the proportion of days covered. RESULTS: Of 3 675 949 initiators, approximately 80% initiated statin use with strong variants. The persistence rate at 1 year was 0.61. Poor adherence to statins during persistence was 8.0% in all patients and this value gradually improved with increasing age. Persistence rate and adherence were lower for the primary prevention cohort than for the secondary prevention cohort, and a notable sex difference was observed for the secondary prevention cohort, which was lower in females but was almost never and slightly observed in the primary prevention cohorts without and with high-risk factors, respectively. CONCLUSIONS: Many statin initiators discontinued statins shortly following statin initiation but adherence while on statin therapy was good. Attentively watching older patients not to discontinue statins and listening to their reasons for discontinuation are required, especially for initiators in primary prevention and females in secondary prevention.

Statin, Ezetimibe, or Fibrate Initiation and Subsequent Use for the Primary and Secondary Prevention of Cardiovascular Diseases among Japanese Patients Aged ≥55 Years: A Nationwide Cohort Study.

The use of lipid-modifying agents (LMAs) other than statins has rarely been reported in real clinical settings. We aimed to compare the initiation and subsequent use of LMA classes for prevention of cardiovascular diseases. Using the national claims database, this retrospective cohort study was conducted on patients aged ≥55 years who initiated to use statins, ezetimibe, or fibrates between Fiscal Years (FYs) 2014 and 2017 as the first pharmacotherapy for dyslipidemia in Japan. A permissible gap for defining persistence was set as the median days of supply of a class to an individual. Kaplan-Meier estimates were calculated for rates. Cohorts for primary prevention without/with risk and secondary prevention comprised 1307438, 908378, and 503059 initiators for statins; 44116, 34206, and 11373 for ezetimibe; and 124511, 96380, and 27751 for fibrates. The persistence rates declined shortly after the therapy initiation regardless of the classes, which was approximately 50% at 1 year for any class for primary prevention without risk. A notable sex difference in terms of persistence rates was observed only for statins of secondary prevention. The restarting rates were similar between prevention settings: approximately 50-60% for statins and 30-40% for ezetimibe and fibrates 1 year after first discontinuation. For ezetimibe and fibrates, approximately 10% of initiators were added or switched to statins within 1 year of initiation. Collectively, any class tended to be discontinued early and some restarted; however, there were some unique classes. The findings are useful for improvement of dyslipidemia therapy.

Chryseobacterium lecithinasegens sp. nov., a siderophore-producing bacterium isolated from soil at the bottom of a pond.

Bacterial strain PAGU 2197T, which was isolated from soil collected from the bottom of a pond in Japan, is characterized in this study. Cells of strain PAGU 2197T were aerobic, Gram-negative, short rod-shaped, non-motile, flexirubin-producing, oxidase-positive, catalase-positive and lecithinase-negative. A phylogenetic study based on 16S rRNA gene sequences and multilocus sequence analysis (gyrB, rpoB and rpoD) indicated that strain PAGU 2197T belongs to the genus Chryseobacterium and is a member of an independent lineage including Chryseobacterium tructae CCUG 60111T (sequence similarity, 95.9 %), Chryseobacterium lactis CCUG 60566T (93.4 %) and Chryseobacterium viscerum CCUG 60103T (91.6 %). The average nucleotide identity values were 80.83-85.04 %. Because average nucleotide identity values of 95-96 % exceed the 70 % DNA-DNA hybridization cutoff value for species discrimination, strain PAGU 2197T represents a novel species in the genus Chryseobacterium. The genome of strain PAGU 2197T was 4 967 738 bp with a G+C content of 35.5 mol%. The sole respiratory quinone of strain PAGU 2197T was MK-6; the major cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3OH, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl); and the major polar lipids were phosphoglycolipids and phosphatidylethanolamine. These results indicate that strain PAGU 2197T should be classified as representing a novel species in the genus Chryseobacterium, for which the name Chryseobacterium lecithinasegens sp. nov. is proposed, with strain PAGU 2197T (=NBRC 114264T=CCUG 75150T) as the type strain.

Fusobacterium watanabei sp. nov. As additional species within the genus Fusobacerium, isolated from human clinical specimens.

Eight spindle-shaped bacteria were isolated from clinical samples in Japan and investigated for their taxonomic position. Phylogenetic trees (based on 16S rRNA, rpoB, zinc protease, and gyrB gene sequence comparisons) showed distinct clustering of eight strains with the type strain of Fusobacterium nucleatum and its closely related species. In silico whole genome comparison analysis based on average nucleotide index based on BLAST (ANIb) and digital DNA-DNA hybridization (dDDH) data between our clinical isolates (PAGU 1795, PAGU 1796T, and PAGU 1797) and the type strain of the closely related species showed values of less than 92.4% and 49.5%, respectively. On the basis of its phylogenetic and genomic distinctiveness together with differential phenotypic properties and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) characteristic signal patterns, we propose Fusobacterium watanabei sp. nov., with the type strain PAGU 1796T (= GTC 21791T = CCUG 74246T).

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale.

Two new azaphilones, namely muyocopronones A (1) and B (2), were isolated from the cultures of an endophytic fungus Muyocopron laterale ECN279. Their structures were elucidated by extensive spectroscopic analysis. Their absolute configurations were determined using the modified Mosher's method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria.

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211.

Talaromycones A (1) and B (2), new xanthenediones, were isolated from the cultures of Talaromyces sp. ECN211, an endophytic fungus, along with α-diversonolic ester (3), aspergillusone B (4), glauconic acid (5), and rosellisin (6). The planar structures of 1 and 2 were elucidated by extensive spectroscopic analyses. Furthermore, the absolute configurations of 1-4 were determined by single-crystal X-ray diffraction and electronic circular dichroism spectroscopy (ECD). In addition, the crystallographic data for 5 were updated for the first time in over 50 years.

Spodiobacter cordis gen. nov. sp. nov., a member of the family Flavobacteriaceae isolated from patients with infective endocarditis.

Two gram-negative, catalase-negative, oxidase-positive strains (PAGU 1467T and PAGU 1468) isolated from patients with infective endocarditis were investigated to determine their taxonomic status. 16S rRNA gene sequence analysis indicated that the two strains were members of the Bergeyella-Chryseobacterium-Riemerella branch of the family Flavobacteriaceae. Strains PAGU 1467T and PAGU 1468 were highly related to each other (98.8% 16S rRNA gene sequence similarity). Phylogenetically closely-related species to PAGU 1467T comprised Bergeyella zoohelcum (95.0% 16S rRNA gene sequence similarity), Riemerella anatipestifer (94.3%) and Cloacibacterium normanense (94.3%). The major fatty acids of the two isolates were iso-C15:0 , iso-C17:0 3-OH and iso-C15:0 3-OH. The presence of C16:0 3-OH and iso-C15:0 2-OH allowed these isolates to be distinguished from B. zoohelcum. Menaquinone MK-6 was the only respiratory quinone in these organisms; this is a consistent characteristic of the family Flavobacteriaceae. The guanine-plus-cytosine content of the genomic DNA was 42.0%, which is higher than that of other close phylogenetic relatives. On the basis of their phenotypic properties and genetic distinctiveness, isolates PAGU 1467T and PAGU 1468 were classified within the novel genus Spodiobacter, as Spodiobacter cordis gen. nov., sp. nov., which is also the type species. The type strain of S. cordis is PAGU 1467T ( = CCUG 65564T = NBRC 109998T ).

Description of Paraclostridium bifermentans subsp. muricolitidis subsp. nov., emended description of Paraclostridium bifermentans (Sasi Jyothsna et al., 2016), and creation of Paraclostridium bifermentans subsp. bifermentans subsp. nov.

Taxonomic studies of strain PAGU 1678T , an obligately anaerobic, gram-positive, spore-forming bacterium isolated from biobreeding rat feces, were performed. This strain has been demonstrated to have the ability to exacerbate pathosis in a mouse model of dextran sulfate sodium-induced ulcerative colitis. Phylogenetic analysis based on the 16S rRNA gene showed high homology with Paraclostridium bifermentans. To clarify the correct taxonomic position of strain PAGU 1678T , a comparative taxonomic study using P. bifermentans PAGU 2008T (═JCM 1386T ) and the closely related bacterial species P. benzoelyticum PAGU 2068T (═LMG 28745T ) was carried out. Despite the close similarity of 16S rRNA gene sequences, DNA-DNA hybridization between strain PAGU 1678T and P. bifermentans PAGU 2008T was 60.03% on average, average nucleotide identity was 96.17%, and it was shown to have different genomic sequences. Biochemically, strain PAGU 1678T could be differentiated from P. bifermentans PAGU 2008T by H2 S production. Furthermore, strain PAGU 1678T was characterized by the presence of two phospholipids with different polarity on polar lipid analysis. In addition, strain PAGU 1678T differed from P. bifermentans PAGU 2008T in findings on whole-cell protein analysis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. On the basis of these biochemical and genetic characteristics, a novel subspecies of P. bifermentans with the name Paraclostridium bifermentans subsp. muricolitidis subsp. nov. is here proposed, with PAGU 1678T (═CCUG 72489T ═NBRC 113386T ) as the type strain, which automatically creates P. bifermentans subsp. bifermentans subsp. nov. JCM 1386T (═ATCC 638T ═DSM 14991T ).

Paraconiothins A-J: Sesquiterpenoids from the Endophytic Fungus Paraconiothyrium brasiliense ECN258.

Paraconiothins A-J (1-10), 10 new sesquiterpenoids, as well as five known sesquiterpenoids, were isolated from the cultures of the endophytic fungus Paraconiothyrium brasiliense ECN-258. The structures of the sesquiterpenoids were elucidated by extensive spectroscopic analysis. Furthermore, the absolute structures of 7 and 8 were determined by comparing their experimental and computed electronic circular dichroism data. Paraconiothins A-G (1-7) were eremophilane sesquiterpenoids, while paraconiothins H-J (8-10) had new or rare carbon frameworks that are possibly biosynthesized by a pathway involving the rearrangement of eremophilane sesquiterpenoids. Paraconiothins C (3) and I (9) exhibited an inhibitory effect on the liver X receptor α at a concentration of 50 µM.

Defining the taxonomic status of Streptococcus suis serotype 33: the proposal for Streptococcus ruminantium sp. nov.

To clarify the taxonomic classification of Streptococcus suis serotype 33, we performed biochemical and molecular genetic analyses using isolates (GUT-183, GUT-184, GUT-185, GUT-186, GUT-187T, GUT-188, GUT-189, GUT-190, GUT-191, GUT-192 and GUT-193) from bovine endocarditis. A comparative sequence analysis showed 99.2-100 % sequence similarity among the reference strain of S. suis serotype 33 and our isolates for the 16S rRNA gene. These similarities were higher than those between the isolate GUT-187T and S. suis and other streptococci. Comparison of sodA genes also showed high degrees of similarities among the reference strain of S. suis serotype 33 and our isolates (99.7-100 %), which were higher than those between the GUT-187T and S. suis and other streptococci. DNA-DNA relatedness among three isolates (GUT-186, GUT-187T, the reference strain of S. suis serotype 33) was over 76.7 %. In contrast, the relatedness between GUT-187T and the other streptococcal species (S. suis, Streptococcus parasuis, Streptococcus acidominimus and Streptococcus porci) was 8.4-24.9 %. Phylogenetic analyses showed that the isolates did not affiliate closely to any known species of the genus Streptococcus. Moreover, GUT-187T could be distinguished from S. suis and other closely related species of genus Streptococcus using biochemical tests. On the basis of the phenotypic and molecular genetic data, we propose that the isolates of S. suis serotype 33 should be classified into the genus Streptococcus, Streptococcus ruminantium sp. nov. with the type strain GUT-187T (=DSM 104980T=JCM 31869T).

Unusual manifestation of Helicobacter cinaedi infection: a case report of intracranial subdural empyema and bacteremia.

BACKGROUND: There have been various reports concerning Helicobacter cinaedi infections. However, few reports have examined central nervous system infections. CASE PRESENTATION: A 52-year-old man was transferred from the local hospital because of a persistent headache and suspected intracranial subdural empyema. Neurosurgical drainage was performed via burr holes. Gram staining and results from abscess cultures were negative. The blood culture yielded H. cinaedi. He was given an antibiotic regimen consisting of 2 g of ceftriaxone twice a day, but the size of the abscess was not reduced in size at all after 3 weeks of treatment. Neurosurgical drainage was performed again, and the antimicrobial regimen was switched to 2 g of meropenem 3 times a day. The size of the abscess was reduced after 2 weeks of the second drainage and antimicrobial drug change to meropenem. After 4 weeks treatment with meropenem, the patient was discharged, and his symptoms had completely resolved. CONCLUSIONS: H. cinaedi infection should be considered in the differential diagnosis of subdural empyema cases for which Gram staining and abscess culture results are negative. Meropenem can be a first-line drug of choice or an effective alternative treatment for H. cinaedi central nervous system infections.

Helicobacter cinaedi bacteremia resulting from antimicrobial resistance acquired during treatment for X-linked agammaglobulinemia.

This is the first report of penicillin/cephalosporin-resistant Helicobacter cinaedi arising from prolonged treatment. H. cinaedi, common among immunocompromised patients, caused recurrent bacteremia and cellulitis in a 19-year-old Japanese man with X-linked agammaglobulinemia. The minimal inhibitory concentration of these drugs was raised, which subsequently resulted in clinical failure. Prolonged suboptimal treatment may cause bacterial resistance to ß-lactam antibiotics in H. cinaedi. It is possible that this resistance may have contributed to the treatment failure.

The first cases of human bacteremia caused by Acinetobacter seifertii in Japan.

Acinetobacter seifertii, a novel species of Acinetobacter, was first reported in 2015. A. seifertii strains were isolated from human clinical specimens (blood, respiratory tract, and ulcer) and hospital environments. Here, we report the first cases of bacteremia caused by A. seifertii in patients with catheter-related bloodstream infection in Japan. The patients favorably recovered, without any complications, after removal of the peripheral intravenous catheters and administration of antibiotics. The pathogens were initially identified as Acinetobacter baumannii, using phenotypic methods and the MicroScan Walkaway System; however, rpoB gene sequence analysis indicated 99.54% similarity to A. seifertii. Moreover, antimicrobial susceptibility testing revealed that one of the strains was not susceptible to gentamicin and ceftazidime. Our report shows that Acinetobacter species other than A. baumannii can also cause nosocomial infections and that accurate methods for the identification of causative agents should be developed.

Porphyromonas bronchialis sp. nov. Isolated from Intraoperative Bronchial Fluids of a Patient with Non-Small Cell Lung Cancer.

Porphyromonas strains, including Porphyromonas-like strains, have been isolated from oral and various other systemic infections. The characterization of such strains is a crucial issue, because such information contributes to both the taxonomy of anaerobic bacteria and the clinical aspects of infectious diseases. We previously isolated four Porphyromonas-like strains from intraoperative bronchial fluids of a patient with non-small cell lung cancer. This study aimed to characterize the genetic, biochemical and chemotaxonomic aspects of these isolates. Each strain only grew under anaerobic conditions and their colony morphology was convex, 0.1-1.0 mm in diameter, light gray, and slightly glistening colony, with no black or brown pigmentation on blood agar plates after five-day incubation. The pigmentation was helpful to differentiate the isolates from other Porphyromonas, as most of Porphyromonas species show the pigmentation. In the 16S rRNA gene phylogenetic analysis (98% sequence identity of isolates indicates the same species), the four isolates were closely related to one another (99.7-100.0%), but not related to Porphyromonas (P.) catoniae, the closest species (96.9%). In addition, the DNA-DNA hybridization data revealed less than 16% similarity values between a representative isolate and the P. catoniae, indicating that the strains were genetically independent. Biochemically, the isolates could be differentiated from closely related species, i.e., P. catoniae, P. gingivalis, P. gulae, and P. pogonae, with trypsin activity (negative only in the isolates) and leucine arylamidase activity (positive only in the isolates). We therefore propose a new species to include these isolates: Porphyromonas bronchialis sp. nov.

Clinical and bacteriological characteristics of Helicobacter cinaedi infection.

Helicobacter cinaedi was first isolated from rectal cultures from homosexual men in 1984. In the 1980s to mid 1990s, the microorganism was mainly isolated from samples from homosexual men or immunocompromised patients; however, during the last two decades, H. cinaedi has been isolated from immunocompromised and from immunocompetent individuals worldwide. In Japan, the isolation of this microorganism was first reported in 2003. Since then, many cases have been reported in hospitals across the country. Despite many reports, the etiological properties and pathogenicity of H. cinaedi remain elusive; however, we are increasingly able to recognize some of the features and the clinical relevance of infection. In particular, a long incubation period is essential for detection in an automatic blood culture system and many of the recent isolates are resistant to both macrolides and quinolones. Furthermore, there is an association between infection and severe or chronic illnesses, such as meningitis or arteriosclerosis, in addition to mild diseases such as fever, abdominal pain, gastroenteritis, proctitis, diarrhea, erysipelas, cellulitis, arthritis, and bacteremia. In this review, we introduce the current knowledge and our latest findings relating to H. cinaedi.

Streptococcus suis subsp. hashimotonensis subsp. nov.: Lancefield group A antigen-positive organisms isolated from human clinical specimens and wild boar oral cavity samples.

Three Streptococcus suis-like strains positive for Lancefield antigen group A were isolated from human boar bite wounds and the oral cavities of boars in Hashimoto City, Wakayama Prefecture, Japan, and their taxonomic positions were investigated. Application of the VITEK2 system identified all three isolates as S. suis with > 94 % probability. The isolates were assigned to S. suis based on the results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis (Biotyper score of 2.382) but were differentiated according to the characteristic signal peaks (4709 m/z and 9420 m/z) that were not present for S. suis. Sequence analysis of the 16S rRNA and sodA genes determined that the isolates were similar to S. suis; however, these genes appeared on a phylogenetic sub-branch. Phylogenetic analysis of the whole chromosomal DNA showed that the isolate formed a cluster with S. suis but with clear divergence. The average nucleotide index using BLAST between the clinical isolate (PAGU 2482) and a closely related reference strain of S. suis was 94.75 %, which was not clearly conclusive; however, digital DNA-DNA hybridization showed a value of 61.2 %. Biochemical reactions, including those with acid phosphatase, α-chymotrypsin, and tagatose (acidification), distinguished our isolates from S. suis. Thus, based on phylogenetic, genomic, and phenotypic characteristics and MALDI-TOF-MS signal patterns, we propose that the isolate with Lancefield group A positive characteristics be designated as a novel subspecies, Streptococcus suis subsp. hashimotonensis subsp. nov., with the type strain PAGU 2482T (GTC 18290T = CCUG 77434T).